Thirty years ago this summer, two spacecraft lifted off from Earth. Both carried a gift for any extra-terrestrial life that might be on the receiving end.

Voyager 1 and its cousin, Voyager 2, carried rock-and-roll by Chuck Berry, jazz by Louis Armstrong, Bach, Beethoven, and other music from around the world.

The 27 pieces were contained in a copper record, accompanied by a needle and playback instructions.

Neither spacecraft will reach another star system anytime soon. Still, scientists are celebrating the anniversary of some of the hardest-working spacecraft in the cosmos.

Originally built to explore Jupiter and Saturn, today Voyager 1 is farther from Earth than any other human-made object and speeding outward at more than 38,000 miles per hour. Both spacecraft are still sending scientific information about their surroundings to Earth.

Carl Sagan

Though three-quarters of the record is taken up with music, a committee chaired by the late Carl Sagan also decided to include pictures from Earth, greetings in 55 languages, and natural sounds from the planet. Science writer Timothy Ferris produced the record, and he says that even today the Voyager time capsules still hold up.

Timothy Ferris

"We thought of the record in terms of presenting some of the things important to us as a species, and music is important to people all over the world even though it's not often possible to say why," says Ferris, who is now an emeritus professor at the University of California, Berkeley and the author of several popular science books, including The Whole Shebang and Coming of Age in the Milky Way. His upcoming PBS special "Seeing in the Dark", will air on Wednesday, September 19."

Ferris says that the committee that chose the music consulted with performers, musicologists, composers, and others before they narrowed down the selections. Naturally, they ran into political pressure.

"Someone told me that we should have an Irish song because Tip O'Neill was Speaker of the House at the time," Ferris recalls.

It will be around 40,000 years before the spacecraft make a close approach to any other planetary system. But Ferris and NASA scientists expect the nuclear-powered Voyager crafts to live on, perhaps one day meeting beings who might give the craft's golden contents a spin.

Liane Hansen spoke with Ferris about the Voyager's music and its long life.